I suggest you ...

Track time against a task

I would like the ability for the person assigned a task to put in how many hours it took to complete the task. It would simplify my billing. I don't need anything fancier than total hours and minutes spent, but some day to add date and time spent would be awesome too.

Tracking number of hours spent on a certain task would seriously help users build better project plan and select appropriate LoE.
Speaking of the LoE drop down, could that be field instead of a drop down? some tasks have longer than 14 days of effort.